"One time I was on a red carpet and Brad Pitt and Angelina Jolie came up to me and they said, 'We just watched Sarah Marshall. We just wanted to say hi. Great job!'" Segel recalled during a Tuesday appearance on The Tonight Show with Jay Leno. "And my response was, 'Oh, my God! It's you!"

Segel was similarly starstruck when he was recently introduced to LadyGaga, former President BillClinton and U2's lead singer, Bono.

"I've never felt more out of place, but I thought, 'It's worth it because I'll remember this moment for the rest of my life.' Then President Clinton came up to talk to me, and at that point, from then on, I have no recollection at all," Segel laughed. "I know he was charming. I don't think I said anything at all. I'm bad with this stuff."